Just flown back from Copenhagen with Norwegian and noticed that their in-flight shopping brochure for Winter 2016/17 lists the Bose QC35s at £255.

Admittedly this isn't the best price that's been seen, but they don't get discounted that frequently or by very much - plus it's cheaper than Dixons Travel were selling them for when I left. Also, I realise that requiring you to take a flight makes this deal rather difficult to obtain, but I thought it might be useful to someone.

EDIT: Obviously, booking a flight specifically to get these is a stupid idea, but if you are already flying Norwegian to anywhere in Scandinavia or long-haul to US, then it may be of use.